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Comment by fs_tab | Hacker News Reader

Somewhat related - be wary of implicit parameter passing in function pipelines. For example, Try ['10', '10', '10'].map(Number.parseInt) in your browser console. What's actually being called is:

Number.parseInt('10', 0) Number.parseInt('10', 1) Number.parseInt('10', 2)

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Typing fixes this, and anonymous records make it even better.

JavaScript lacks typing, and then they decided on a weird signature for the callback...

Unfortunately typing doesn't fix this. The 2nd callback function argument of Array.map is (index:number), and the 2nd argument of Number.parseInt is (radix:number).

It's a very nasty issue to debug.

If there were typing, there would be no reason to not use newtypes[0] for radix and index. These values should only be explicitly unwrapped to plain numbers.

It would look like this

    newtype Radix = Radix { radixToWord :: Word }
    newtype Index = Index { indexToWord :: Word }

[0]: https://wiki.haskell.org/Newtype

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